JPH05154816A - Manufacturing method of fiber reinforced cement board - Google Patents

Abstract

(57) [Summary] [Purpose] The objective is to rapidly form a thick fiber-reinforced cement board without impairing the strength. [Constitution] The cement slurries (S) are layered on the upper surface of a water-permeable molding belt (B) having suction and dehydration devices (11) to (14) on the lower surface, and the water content contained in the suction and dehydration device (11) is increased. While suction-dewatering, the surface is made of synthetic resin with good peelability and compressed with a compression roll (50) to make a plate, and then the cement slurry (S) is layered on the plate (G). To the suction dewatering device (12) while sucking and dewatering the water content, a compression roll whose surface is made of a synthetic resin having good releasability as described above (5
Repeatedly compressing and stacking in 1) to stack and form the plate body (G) to a predetermined thickness, and finally apply air pressure from the back surface of the forming belt with pressurized air (54) to form the forming belt.
The process consists of peeling from (B) and transferring to the curing process,
Quickly molds thicker below without the use of making rolls.

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a method for producing a fiber-reinforced cement board, and more particularly to an improvement in a method for producing a fiber-reinforced cement board in which slurry is layered on a forming belt.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a fiber-reinforced cement board, cement slurry is supplied in layers on the upper surface of a water-permeable molding belt having a suction dehydration device on the lower surface, and the moisture content is suction-dehydrated by the suction dehydration device. There is known a so-called flow-on molding method in which a plate is formed while being pressed, and the plate is rolled while being compressed by a making roll to be laminated to a predetermined thickness, and the plate is cut and flattened to form a plate. This kind of manufacturing method was developed as an improved technique for preventing the segregation of the material for making up the cement slurry in the so-called papermaking method, and in particular, it is made by the cement compound containing pulp fiber having a low specific gravity or porous lightweight aggregate. When the plate is used, it is effective to achieve uniform dispersion of such a lightweight compound material in the product.

[0003]

[Problems of the prior art] However, since the above-mentioned manufacturing method has a step of winding and laminating a plate-making body made of cement slurry on a making roll until a predetermined thickness is obtained, and then cutting and flattening it, the manufacturing method becomes a batch system, There was a problem that production efficiency was poor because continuous production was not possible. In addition, the method of abolishing the stacking on the making roll, supplying the cement slurry in layers at a stretch to the desired thickness on the forming belt, and compressing it with the rolls to make a sheet is possible on the forming belt even though continuous production is possible. Since the layer thickness to be layered becomes thicker, it is difficult to form a layer of uniform thickness, and it takes much time for suction and dehydration, and it is necessary to extremely slow down the transfer speed of the molding belt. There was a flaw that I could not do.

[0004]

In view of the above problems, the present invention can efficiently produce a fiber-reinforced cement board having a thick layer at a speed comparable to that of the dry method without impairing the advantages of the flow-on method. The purpose is to obtain a manufacturing method.

[0005]

That is, the method for producing a fiber-reinforced cement board according to the present invention comprises supplying the cement slurry in a layered manner to the upper surface of a water-permeable molding belt having a suction dewatering device on the lower surface, and performing the suction dewatering. While sucking and dehydrating the water content in the device, the surface is compressed by a compression roll made of a synthetic resin having good releasability to form a plate, and then cement slurry is further supplied in layers on the plate body, While sucking and dewatering the water content with a suction dewatering device, the surface is made of a synthetic resin having a good releasability in the same manner as described above, and the plate is made up to a predetermined thickness by repeatedly laminating by compression with a compression roll. It is characterized in that it is laminated and molded, and finally, it is peeled from the molding belt by applying air pressure from the back surface of the molding belt and pressurized, and transferred to the curing step.

[0006]

In the present invention, the cement slurry used is the same as the cement slurry used in the conventional flow-on process, for example, 40 to 50% by weight of cement, 40 to 50% by weight of silica sand powder, and pulp fiber 3 ~ 8% by weight, lightweight aggregate 3-5% by weight, etc., with 400-800% by weight of water added to the outside ratio, and uniformly kneaded.Especially in terms of material composition and water content, etc. There is no point to do.

[0007] In the present invention, during plate making, cement slurry is supplied in layers on a long permeable forming belt, suction dewatering is carried out, water content is sucked and dewatering, and it is compressed with a roll to make a plate, and then In order to form a product by further supplying cement slurry to the above and repeating the same plate-making process until the product has a predetermined thickness, the plate-making body is successively formed on a continuous forming belt. It is possible to perform continuous molding by stacking and molding.

Further, the compression of each of the plate-made layers is carried out by a compression roll whose surface is made of a synthetic resin having good releasability. The synthetic resin having good releasability refers to, for example, a polymer resin such as polyethylene and the like, and enables compression without adhesion of cement slurry without using a release agent or the like. Further, in carrying out this production method, it is possible to add arbitrary different color pigments to the cement slurry to be laminated.

[0009]

Embodiments of the present invention will be described below. FIG. 1 is a side view of an apparatus for carrying out the method of the present invention. 5% by weight of water for a fiber-reinforced cement mixture consisting of 46.5% by weight cement, 46.5% by weight silica sand powder, and 7% by weight pulp fiber.
Cement slurry S was obtained by adding 00% by weight and uniformly mixing.

Next, the first to fourth flow boxes 10 are provided on the front side.
˜40 and correspondingly, suction boxes 11 to 41 for suction / dehydration on the back surface are prepared, and a felt water-permeable molded belt B having a width of 1 m is prepared. First, the cement slurry S is fed from the first flow box 10. Is supplied as a layer with a thickness of approximately 0.6 cm,
It was sucked and dehydrated by the suction box 11 and was compressed at a linear pressure of 60 kg / cm by a compression roll 50 having a polyethylene layer on the surface to form a layer having a thickness of 0.12 cm. Next, the cement slurry S is again fed onto this layer G in the form of a layer having a thickness of about 0.6 cm, and is suction-dehydrated by the suction box 11 and a linear pressure of 60 kg / cm by a compression roll 51 provided with a polyethylene layer on the surface. Compressed with, and layered to a thickness of 0.25 cm. This was carried out similarly for the third flow box and the fourth flow box, and finally a laminated plate having a thickness of 0.5 cm was formed. Then, at the final end B ′ of the molding belt, compressed air was applied from the air box 54 from the back surface of the belt to float and separate the molded body from the belt B and transfer it to the next transfer belt B1. The time required to obtain the final laminate G was about 1 minute with a belt length of 50 m. This was cut into pieces each having a length of 2 m, transferred to a curing step, and after being naturally cured for 48 hours, the above high temperature and high pressure curing was performed by an autoclave.

As a comparative example, a molding belt B having only one flow box 10 as shown in FIG. 2 was used, and a cement slurry S having the same composition as that of the embodiment was supplied in layers so as to have a volume of about 2 cm. Roll while sucking and dehydrating at 11
A cement board having a thickness of 0.6 cm was obtained by compressing at 50, but it was difficult to uniformly supply the material over the entire width of the belt, and a board having a uniform thickness could not be obtained.

Next, a bending strength test was conducted on the cured plate body cut into a width of 45 cm and a length of 90 cm in accordance with JIS 4, and in the example, a bending strength of 170 kg / cm ² was formed by a conventional manufacturing roll. What was done was also 173 kg / cm ² . As described above, in the case of the method of the present invention, subsequent cutting, makeup, and final pressurization can be performed in a continuous process without deteriorating the bending strength of the obtained plate body as compared with the conventional manufacturing method. It was possible to achieve manufacturing efficiency comparable to.

[0013]

As described above, according to the method of the present invention, a product having the same strength as the product obtained by the conventional flow-on manufacturing method is manufactured at a manufacturing speed comparable to that of the conventional dry manufacturing method. This has the excellent effect of significantly increasing the production efficiency.

[Brief description of drawings]

1 is a side view of an apparatus for carrying out the method of the present invention.

FIG. 2 is a side view of an apparatus for carrying out the method of the comparative example.

FIG. 3 is a side view of an apparatus for performing a conventional flow-on manufacturing method.

[Explanation of symbols]

 10 1st flow box, 11 to 41 suction box, 20 2nd flow box, 30 3rd flow box, 40 4th flow box, 50 to 53 Compress roll 54 Compressed air box

Claims (1)

[Claims] 1. A synthetic resin having a peelable surface while the cement slurry is supplied in layers on the upper surface of a water-permeable molded belt having a suction dewatering device provided on the lower surface, and the water content is sucked and dewatered by the suction dewatering device. Compressed with a compression roll made into a plate to make a plate, then further supplying cement slurry on the plate body in a layered form, while sucking and dehydrating the water content in the suction dehydrator, the surface is the same as above. By repeatedly compressing and laminating with a compression roll made of synthetic resin with good peelability, the plate body is laminated and molded to a predetermined thickness, and finally the air pressure by the pressurized air is applied from the back surface of the molding belt. A method for producing a fiber-reinforced cement board, which comprises peeling from a forming belt and transferring to a curing step.